1. Technical Field
The present disclosure relates to aircraft safety systems.
2. Description of the Related Art
Throughout the history of flight, and continuing today, aircraft accidents occur as a result of pilots unknowingly permitting their aircraft to depart from an attitude of controlled flight and entering the regime of uncontrolled flight. Presently, there are three primary flight resources by which a pilot can determine an aircraft's flight attitude; 1) the visual horizon or physical surroundings, 2) an attitude indicator (not present in all aircraft), and 3) a turn and bank indicator (limited to bank indications only).
The pilot monitors these resources singularly or in combination to maintain and verify the flight attitude of the aircraft. Should pilot monitoring or the reliability of these resources be compromised, an aircraft's flight path can quickly deteriorate into a dangerous attitude that can result in the total loss of aircraft control and subsequent disaster. Even with present day sophisticated instruments, accidents still occur when pilots become disoriented or their attention is diverted away from aircraft attitude. Present day flight instruments represent “present” aircraft attitude. With the exception of the stall warning horn, they have no capability to warn of “pending” uncontrollable flight attitude. Even the stall warning system doesn't alert the pilot of the aircraft's attitude, only that the angle of attack is approaching the maximum angle that the wing will sustain aerodynamic lift.
The most prominent cause of inadvertent departure from controlled flight is spatial disorientation. Spatial disorientation can be defined quite simply as the inability to correctly orient oneself with respect to the earth's surface. Spatial disorientation in aviation occurs when an aircraft moves into an awkward and unsafe flying attitude without the pilot's awareness.
All pilots, student pilots to professional and military pilots, are susceptible to spatial disorientation. Federal Aviation Agency statistics indicate that 15-17% of all aviation accidents, which includes commercial airlines, are the result of spatial disorientation and 90% of these accidents are fatal. Spatial disorientation is the military's number one cause of fatal accidents.
Even the best of pilots will quickly become disoriented if they attempt to fly without instruments when there are no outside visual references. That's because vision provides the predominant sense we rely upon for spatial orientation. Therefore spatial disorientation most commonly occurs when the horizon or other outsides references are obscured, such as when clouds, haze, fog, snow or darkness are present. Loss of ability to determine the planes position via the horizon leads to disorientation and severe loss of flight control with potentially fatal results.
Instrument flight training instructs pilots in coping with spatial disorientation. However, an instrument rating does not make a pilot immune to spatial disorientation and its potential for disaster. Also, approximately 80% of the private pilots in the United States are not instrument rated. This does not stop some non-instrument rated pilots from continuing flight into conditions for which an instrument rating is required. According to the National Transportation Safety Board, 40% of the fatal general aviation accidents are because of this indiscretion. Current aviation accident statistics indicate that prior art continues to be insufficient to protect pilots from the hazards of spatial disorientation.